1. Field of the Invention
The present invention relates to an image transfer material, and a process for printing images using toner, pigmented, and/or water soluble colorants from a heat transferable material having an image receiving layer, which image receiving layer contains 1) precipitated calcium carbonate (PCC), 2) polyvinylpyrrolidone (PVP), or 3) a combination of PCC and PVP (PCC/PVP). More specifically, the present invention relates to an image transfer sheet which can be applied to a receptor element, such as cotton or cotton/polyester blend fabrics or the like.
2. Description of the Prior Art
Textiles such as shirts (e.g., tee shirts) having a variety of designs thereon have become very popular in recent years. Many shirts are sold with pre-printed designs to suit the tastes of consumers. In addition, many customized tee shirt stores are now in the business of permitting customers to select designs or decals of their choice. Processes have also been proposed which permit customers to create their own designs on transfer sheets for application to tee shirts by use of a conventional hand iron, such as described in U.S. Pat. No. 4,244,358. Furthermore, U.S. Pat. No. 4,773,953, is directed to a method for utilizing a personal computer, a video camera or the like to create graphics, images, or creative designs on a fabric. These designs may then be transferred to the fabric by way of an ink jet printer, a laser printer, or the like.
Other types of heat transfer sheets are known in the art. For example, U.S. Pat. No. 5,798,179 is directed to a printable heat transfer material using a thermoplastic polymer such as a hard acrylic polymer or poly(vinyl acetate) as a barrier layer, and has a separate film-forming binder layer. U.S. Pat. No. 5,271,990 relates to an image-receptive heat transfer paper which includes an image-receptive melt-transfer film layer comprising a thermoplastic polymer overlaying the top surface of a base sheet. U.S. Pat. No. 5,502,902 relates to a printable material comprising a thermoplastic polymer and a film-forming binder. U.S. Pat. No. 5,614,345 relates to a paper for thermal image transfer to flat porous surfaces, which contains an ethylene copolymer or a ethylene copolymer mixture and a dye-receiving layer.
Other examples of heat transfer materials are disclosed by, for example, U.S. application Ser. No. 09/541,083 filed Mar. 31, 2000 which relates to relates to a polymeric composition comprising an acrylic dispersion, an elastomeric emulsion, a plasticizer, and a water repellant. U.S. application Ser. No. 09/557,173 filed Apr. 21, 2000 relates to a barrier layer. The barrier layer of Ser. No. 09/557,173 provides for “cold peel,” “warm peel” and “hot peel” applications and comprises thermosetting and/or ultraviolet (UV) curable polymers. Provisional application 60/134,849, filed May 19, 1999 relates to a transferable material having a transfer blocking overcoat and to a process using said heat transferable material having a transfer blocking overcoat. The transfer blocking overcoat of 60/134,849 allows for the reduction of the polymer halo around the transferred image while still providing for the “hand” or feel of the substrate after transferring.
Some of the above-mentioned applications contain specific systems for forming clear images which are subsequently transferred onto the receptor element. However, other heat transfer systems exist, for example, those disclosed by U.S. Pat. Nos. 4,021,591, 4,555,436, 4,657,557, 4,914,079, 4,927,709, 4,935,300, 5,322,833, 5,413,841, 5,679,461, and 5,741,387.
However, one problem with many known transfer sheets is poor image quality of the printed images. Poor image quality can result when using any conventional printing process, such as, for example, ink jet printing, laser printing, lithographic offset printing, and any standard surface-to-surface printing processes. The present invention corrects this problem.
Some examples of poor image quality include fuzzy edges, mottled image areas and/or faded images which may sometimes occur in an ink jet application of an image area onto a conventional sheet substrate. These properties result due to the fact that the thermal ink jet process applies a dilute aqueous ink onto the surface of the recording paper by heating a small volume of the ink in a small chamber with an orifice that is directed at the recording paper. The small volume of ink that is heated rapidly reaches its boiling point, and the steam bubble formed propels a tiny drop of liquid ink at the paper, where the drop produces a single dot in a dot matrix that forms a character or image on the sheet. This process requires an ink that is low in solids and high boiling components so that it is capable of boiling rapidly without leaving a residue that can foul the heating element, and clog the orifice. Therefore, up to 96% of conventional ink jet printer ink is a mixture of water and low molecular weight glycols. Although such an ink boils quickly when heated to ensure rapid printing, and is not prone to clog, it results in an applied ink that is very mobile and slow to dry. Therefore, good print quality can be obtained only if the ink colorant or dye remains on or near the outer surface of the paper, and does not spread or move from the point at which it was applied. Accordingly, when these images are transferred onto a receptor element such as a T-shirt, the poor image quality is reproduced in the final product.
The prior art has attempted to address this problem of poor ink/paper substrate interaction and/or high ink absorption into the paper substrate. For example, several references discuss the use of an image receiving layer upon which the image is deposited. However, current systems are generally provided with a coating in which the pigment is a finely divided silica. However, these systems are unable to solve the problem associated with poor ink/paper interaction and/or high ink absorption into the paper substrate. Thus, the image transferred to the receptor element is flawed.
Accordingly, there continue to exist problems associated with transferring an image to a substrate, wherein the image is of good quality, having sharp edges, dense coloring and no mottled image areas. The present inventors have found that these problems may be solved by utilizing the image receiving layer according to the present invention.